The common theme of this program project is the regeneration and transplantation of mammalian skeletal muscle. There are four major areas of emphasis in the program: 1) Reintegration of regenerating muscle with the vascular and nervous systems of the host; 2) regulation of genetic expression and protein synthesis in regenerating muscle; 3) devising means of improving the mass of muscle that can be transplanted and improving the functional properties of a given regenerated muscle; 4) in vivo evaluation and prediction of the structure and function of grafted models. Emphasis of component projects is as follows: Daniel Axelrod - dynamics and localization of acetylcholine receptors; Kate Barald - interactions between regenerating muscle and nerve fibers in vitro; Bruce Carlson - interactions between regenerating muscle and nerve in vivo; John Faulkner - revascularization of regenerating muscle; Carl Gans - electromyographic evaluations of the structure and function of regenerating muscle. George Jones - regulation of protein synthesis in regenerating muscle; Jessica Schwartz - hormonal regulation of muscle regeneration; Timothy White - effects of physical conditioning on regenerating muscle.